Work-clamp for buttonhole-sewing machines.



No. 758,036. PATENTBD APR. 26, I904.

E. B. ALLEN.

WORK CLAMP FOR BUTTON HOLE SEWING MACHINES.

APPLICATION IILBD SEPT. 2. 1903.

K0 MODEL,

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No. 758,036. PATENTED APR. 26, 1904. E. B. ALLEN. WORK CLAMP FOR BUTTONHOLB SEWING MACHINES.

APPLICATION FILED SEPT. 2, 1903. N0 MODEL. 2 SHEET8SHEET 2.

"mm." 2 II II awvamtoz UNITED STATES Patented April 26,1904.

PATENT OFFICE.

EDWARD B. ALLEN, OF ELIZABETH, NEWJERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

WORK-CLAMP FOR BUTTONHOLE-SEWING MACHINES.

SPECIFICATION forming part of Letters Patent No. 758,036, dated April 26, 1904.

Application filed September 2, 1908. Serial No. 171,631. (No model.) 1

To all whom it may concern:

Be it known that I, EDWARD B. ALLEN, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in VVork-Clamps for Buttonhole-Sewing Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to work-clamps for buttonhole-sewing machines, and has'for its object to provide a work-clamp of comparatively simple construction which will automatically stretch the work or material transversely of a buttonhole when the force by which the clamp is opened is released to permit the clamp to close, so that if the buttonhole he cut before being stitched the slit will be properly spread or opened for the stitching operation, and if the buttonhole is to be cut after tlre stitching operation the material will be under such transverse tension during the stitching operation as to enable the latter to be perfectly performed and will also be under such transverse tension at the cutting operation as to facilitate such cutting operation to insure a smooth out.

In the accompanying drawings, Figures 1 and 2 are respectively front and side elevations of an apparatus embodying the present invention, and Fig. 3 is a plan view of the same.

Re erring to the drawings, 12 denotes What may properly be termed the base-plate of the clamp, and to the bottom of which baseplate is attached the lower clamp-plate 13, which is mounted to slide or travel lengthwise of the buttonholes on the shifting-plate 14, carrying the throat-plate 15, having the needle-opening 16 and the cutter-slit 17.

The means for imparting feeding and shifting movements to the clamp form no part of the present invention, but may be similar to or the same as those fully shown and described in my United States Patent No. 738,591, granted September 8, 1903.

The base-plate 12 is provided with a fulcrum-block 18,, on which is pivotally mounted by a pin 19 a block 20, to which is attached the upper plate 21, carrying the clampingarms 22, pivotally attached at their rear ends by the screws 23 to the said plate 21 and provided at their forward ends with the clamping-feet 24c, constituting the upper members of the clamp. The clamping-arms 22 are provided with small hooks 25, connected by a spiral spring 26, serving to draw the said arms toward each other. Mounted in the plate 21 is a small rocker 27 having at its upper end an operating-arm 28 and at its lower end a cam device 29, interposed between the clamping-arms 22, so that by turning the said cam device the said arms may be spread apart in opposition to the stress of the spring 26, tending to draw them together. Instead of directly engaging the arms 22 the said cam preferably engages abutment plates or blocks 30,

adjustably secured to said arms, so that by adjusting said plates or abutments inward or outward the stretching movements of the clamping-arms by the cam device 29 may be varied for different widths of seams.

The inward movements toward each other of the clamping-arms 22 under the stress of the spring 26 are preferably limited by a pin 31, the lower end of which occupies the V- shaped space between the rear parts of said arms, said pin being adjustably secured to the upper plate 21, so that by adjusting it toward or from the pivotal points of said arms the space between the clamping feet or members 2 1 at the forward ends of said arms when said feet or members are drawn togetherby the spring 26 may be varied for different widths of stitching. The adjustment of the abutment plates or blocks 30 will compensate for the adjustment of the stop-pin 31, so that the spread.

ing movements of the clamping-arms will always remain the same.

Fixed to the clamp base-plate 12 is a post 32, which is threaded at its upper end for the reception of an adjusting-nut 33, between which and a collar 341 on said pin is interposed a clamping spiral spring 35, which normally presses the upper clamping members or feet 2 1 down on the work or material interposed between said members or feet and the lower clamp-plate 13. The pivotally-mounted upper plate 21 is extended diagonally rearward in the-form of an arm, which is to be connected with a suitable treadle to be depressed by the attendant to release the force of the clamping-spring 35 when the clamp is to be opened. Instead, however, of connecting the treadle directly to the plate 21 it is indirectly connected therewith through a tilting block or lever 36, pivotally mounted on the plate 21 and normally having its forward end pressed against said plate by a spring 37, which, however, is weaker than the clamping-spring 35, but much stronger than the spring 26. The rear arm of the tilting block or lever 36 is provided with \a hook 38, to which the treadle rod or chain is to be attached, and said rear arm is also preferably provided with an adjustable abutment-pin 39,-which limits the rearward tilting movement of the block or lever 36 when the treadle is depressed to open the clamp. The position of the abutment-pin 39 may be varied to regulate the movements of the tilting block or lever 36, and thus vary the spreading movements of the clampingarms by varying the extent of the torsional movements of the cam 29. The forward arm of the block or lever 36 is connected by a pitman 40 with the arm 28 of the rocker 27 so that as the said block or lever is tilted or moved on its pivot the said rocker will have a torsional movement imparted to it to turn the cam device 29, mounted on said rocker, for the purpose of causing spreading movements to be imparted to the clamping-arms 22 after the work is clamped or for the purpose of permitting said arms to be retracted or drawn together by the spring 26 in readiness for a new spreading operation.

In the use of the improved clamp the attendant when adjusting the work for a buttonhole stitching operation depresses the treadle connected with the hook 38 on the tilting block or lever 36. The first part of the downward movement of the treadle compresses the spring 37 and tilts the block or lever 36 before the clamping-feet are lifted from the work or the lower clamp-plate, as the case may be, owing to the fact that the said spring 37 is weaker than the clamping-spring 35, and as the continued downward movement of the treadle (after the abutment-pin 39 comes in contact with the plate 21) opens the clamp by lifting the clamping-feet 2 1 the clampingarms, now released from the spreading-cam, (which was turned to non-spreading position 'when the block or lever 36v was tilted rearward,) will be free to be drawn toward each other by the spring 26. When the material is properly located in the clamp, the attendant releases the treadle and the spring 35 closes the clamp, and owing to the fact that the said spring 35 is much stronger than the spring 37 the latter spring will remain compressed until the clamping-feet 2 1 are firmly pressed on the material by the spring 35 in the relative positions denoted by dotted lines, Fig. 3, when the spring 37 will tilt the block or lever 36 forward and the latter, through the pitman 40, will turn the rocker 27 and the cam 29, carried thereby, and thus automatically force the clamping-arms 22 apart (see full lines, Fig. 3) to spread the material now held in the clamp. The spreading movements of the clamping-arms are, of course, in opposition to the stress of the closing-spring 26; but as the spring 37 is much stronger than the comparatively light spring 26 said spring 37 will much more than overcome the stress of said spring 26 in automatically effecting the spreading operation. Also when the clamp is opened by the depression of the treadle device by the attendant the clamping-arms are automatically restored to their inward or closed positions by the spring 26 in readiness for a new spreading operation.

The invention is not to be understood as being limited to the details herein shown and described, as these may be varied widely without departing from the spirit of the invention. For example, a torsionally-moving and I automatically operating spreading device having pin and slot connections with the clamping-arms may be employed so as to move them from and toward each other positively.

Having thus described my invention, I claim and desire to secure by Letters Patent 1. In a work-clamp, the combination with clamping elements, a spring for closing the same together, and non-automatic means by which the clamp may be opened, of a springactuated rotary cam device for spreading the clamping elements after the force which opens .the clamp has been released to permit the closing-spring to close the clamp; whereby the clamping elements will be closed on the work and then spread apart by a single movement.

2. In a work-clamp, the combination with spring-closed clamping elements, of a spring and connections for automatically spreading said clamping elements after the clamp has been closed, and a spring weaker than the last-named spring, for retracting the spreadapart clamping elements when the said elements have been relieved from the force of the spreading-spring.

3. In a work-clamp, the combination with clamping elements and a spring for closing the same on the work to hold the latter, of a spreading-spring weaker than the first-named spring, and a cam device operatively connected with said spreading-spring, whereby said clamping elements will be automatically spread after the clamp has been closed by its closing-spring.

4. In a work-clamp, the combination with clamping elements and a spring for closing the same, of a spreading-spring weaker than the said closin -spring, a spreading-cam de vice operatively connected with said spreading-spring, and a retracting-spring, weaker than said spreading-spring, operating in opposition to said spreading cam and spring.

5. In a work-clamp, the combination with clamping elements mounted for movements toward and from each other, of an automatic spreading device for said clamping elements, means for drawing said clamping elements toward each other after they have been spread, and an adjustable stop by which the inward positions of said clamping elements may be limited as may be desired.

6. In a work-clamp, the combination with clamping elements and an automatic springactuated rotary spreading device for the same, of adjusting means whereby the spreading movement may be regulated as may be desired.

7. In a work-clamp, the combination with a pivotally-mounted plate, of clamping-arms pivotally attached to said plate so as to be movable toward and from each other at their free ends, a spring for drawing said arms toward each other, a spreading-cam interposed between said arms, and a spring-actuated tilting block or lever carried by said pivotallymounted plate and operatively connected with said cam to operate the same to cause the material to be spread after it has been clamped.

8. In a work-clamp, the combination with spring-closed clamping elements mounted for movements toward and from each other, of an automatically-operated rotary spreading de vice arranged between and acting directly on said clamping elements to force the same apart to spread the work after the said clamping elements have been closed to engage the material to be clamped.

9. In a work-clamp the combination with the base-plate 12, of the lower clamp-plate 13 attached thereto, the upper plate 21 pivotally mounted on said base-plate, clamping-arms pivotally mounted on said plate 21, a spring for drawing said arms toward each other, the rocker 27 having the arm 28 and cam 29, the tilting block or lever 36 mounted on said plate 21, the spring 35 for operating said block or lever, and the pitman connecting said block or lever with the said arm 28, and treadle connections for operating said tilting block or lever and said pivoted plate 21.

10. In a work-clamp, the combination with clamping elements, a spring for closing the clamp, and non-automatic means by which the clamp may be opened, of mechanism, actin g independently of said spring, for spreading the clamping elements after the force which opens the clamp has been released to permit the spring to close the clamp; whereby the clamping elements will be successively closed on the work and spread apart by a single movement.

11. In a work-clamp, the combination with clamping elements and an automatic springactuated spreading device for the same, of adjusting means, independent of the clamping means, whereby the spreading movement may be regulated as may be desired.

12. In a work-clamp, the combination with clamping elements and treadle-actuated means for opening the clamp, of independently-acting means for successively closing the clamp and spreading the clamping elements by a single actuating movement, and a common connection between said clamp-closing and clamp-spreading means and the treadle device, whereby the closing and spreading actions take place when the treadle device is re leased.

13. In a work-clamp, the combination with clamping elements,andtreadle-actuatedmeans for opening the clamp, of independently-acting means for successively closing the clamp and spreading the clamping elements by a single actuating movement, and a common connection between said clamp-closing and clamp-spreading means and the treadle-actuated device; whereby the closing and spreading actions take place when the treadle-actuated device is released, said clamp-closing and clamp-spreading means being so constructed and arranged that the positive actuation of the treadle device acts to successively restore the same to initial position in the reverse order.

14. The combination with a work-clamp, and means for closing, means for opening, and spring-actuated means for spreading said clamp, of means through which the beginning of the spreading action of the said springactuated clamp-spreading means is restrained until the clamp is firmly closed upon the work. 15. The combination with a work-clamp and means for closing, means for opening, and spring-actuated means, operating independent of the closing means, for spreading said clamp, of means through which the beginning of the spreading action of the said spring-actuated clamp-spreading means is restrained until the clamp is firmly closed upon the work.

In testimony whereof I afiix my signature in presence of two witnesses.

EDWARD B. ALLEN. Witnesses:

HENRY J. MILLER, HENRY A. KORNEMANN. 

